Since the SAR, costing and valuation methods have been used increasingly to
quantify the cost of potential impacts; these costs include the costs of adaptations
required specifically to respond to climate change and climate variability,
as well as the costs of residual damages. The bulk of this section focuses on
the foundation of economic costs, but there are metrics other than the economic
paradigm; these are reviewed briefly in Section 2.3.6.

Researchers have adapted fundamental costing and valuation techniques drawn
from the economic paradigm to handle the complexities of increasingly intricate
applications. Market mechanisms provide important ways with which we can aggregate
across a diversity of individual valuations, but they are tied to historical
distributions of resources. Other mechanisms have been exercised, and this section
begins by displaying their conceptual foundations within the economic context
from which they have all evolved. It proceeds by suggesting how relaxing each
underlying economic assumption has been a conceptual challenge. Many of the
responses to these challenges, however, are now part of the general economic
paradigm.